[dredmorbius]

More to the point: the energy-intensive aspect of heating an ICE car, the heat itself, is a waste product of the engine and needs to be removed regardless. Even in cold weather.

In an EV, heat must be generated at a very high energy expense. You can play with the mileage range estimator on Tesla's website. For the largest capacity (85 kWh) batter, heat knocks range down by about 50 miles. Depending on conditions, at 55 MPH, you're talking 350 to 300 or so with heat at 32F. A gasoline powered ICE will likely actually get slightly higher performance due to greater thermal gas expansion at low temperatures, and lower overall cooling demand: while running the cab heater doesn't consume much power, spinning the radiator fan does, and can usually be avoided in cold weather.

Source: http://www.faqs.org/faqs/autos/gasoline-faq/part3/